Towards Responsible Mining: SEMARNAT’s Environmental Framework

As part of the government's effort to develop more robust environmental regulations, the Ministry of Environment and Natural Resources (SEMARNAT) is currently reviewing and updating several of the key official standards (NOMs) that govern mining operations in Mexico, from exploration to tailings management.

Luz Mariana Pérez, Director of Regulation for the Mining and Metallurgical Industry, SEMARNAT, notes that the sector is regulated by a hierarchy of laws, beginning with Constitutional Art. 27, which establishes that minerals are the property of the nation. This is followed by federal laws such as the Mining Law and the General Law on Ecological Balance and Environmental Protection (LGEEPA), as well as their associated regulations and specific NOMs. She stressed that SEMARNAT should not only be seen as an environmental authority but also as “an ally for compliance and a facilitator for ensuring that environmental matters in the mining industry are met.”

During Mexico Mining Forum 2025, Pérez noted that Art. 32 Bis of the Organic Law of the Federal Public Administration (LOAP) outlines SEMARNAT's responsibilities, which include evaluating Environmental Impact Statements (EIAs) for mining projects, which is handled by its Directorate General for Environmental Impact and Risk (DGIRA). The ministry is also responsible for regulating hazardous materials, mining waste, and mine restoration programs through its General Directorate for the Comprehensive Management of Hazardous Materials and Activities (DGGIMAR). To strengthen this role, Pérez explained that SEMARNAT is reinforcing its internal processes and working closely with the Ministry of Economy to resolve many of the pending procedures that had previously slowed the sector. “The goal is that through SEMARNAT’s initiatives we can guarantee an optimal response time for all. Whether the outcome is favorable or not, the important thing is that companies know it, and that they are fully aware of the status of the procedures that matter to them.”

She added that efforts to streamline processes are not limited to new projects. “All of these regulatory initiatives currently being promoted would not only apply to projects that are about to begin operations but also to processes that are already operating today. We will always seek to ensure that the transition provides adequate space to comply with these initiatives.” DGGIMAR, she highlighted, oversees policies on hazardous waste, registers mining and metallurgical waste management plans, and is responsible for issuing, suspending, or revoking authorizations for Mine Restoration, Closure, and Post-Closure Programs.

Pérez also provided an update on the current status of several NOMs specific to mining. The standards for gold, silver, and copper ore leaching systems (NOM-155 and NOM-159) remain current, while the standard for direct mineral exploration (NOM-120) is undergoing a systematic review in 2025. Other important NOMs are in the process of being updated: NOM-157 for mining waste management plans is pending publication in the Federal Official Gazette (DOF), the proposal to update NOM-141 for tailings dams is under analysis, and a preliminary draft for a new NOM-147 on contaminated soil remediation is being developed by a working group.

She emphasized that the process of modifying or issuing a regulation is never unilateral but always grounded in technical studies that incorporate the perspectives of different stakeholders. Academia, she noted, often approaches the issue from an ideal standpoint, while industry brings forward the practical challenges of compliance. 

“It is of no use to overwhelm them with regulatory instruments if these are going to be unattainable. It is important to reach that balance, and for that our participation and collaboration with the mining chamber has been key,” she concluded.